Belt Drive

Discussion in 'Inboards' started by fpjeepy05, Mar 22, 2011.

  1. anthony goodson
    Joined: Mar 2007
    Posts: 439
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    No you simply incorporate a deep groove angular thrust bearing into the cage on the end of the propeller shaft and make sure that it and the cage are anchored well enough to withstand the thrust from the prop. No need for any expensive or complicated parts. I am playing the devil's advocate here a bit ,and don't necessarily think this is the way to go as Frosty said "what's wrong with a gearbox." However if you are determined then this might help ,or at least be food for thought.
     
  2. anthony goodson
    Joined: Mar 2007
    Posts: 439
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    Frosty they say that necessity is the mother of invention ,and the price of oil will shortly be that necessity. If they ever import one of these into the UK ,it will go straight into a museum. Petrol is now £1.35 a litre and rising ,diesel even worse.
     
  3. fpjeepy05
    Joined: Jan 2010
    Posts: 248
    Likes: 14, Points: 18, Legacy Rep: 31
    Location: Hubert, NC

    fpjeepy05 Senior Member

    557hp from 1000 pounds motor to prop. Pretty impressive if you ask me. Compared to the yamaha 350hp at 804lbs. Only applicable to boats that where running triples and quad 350s. How much does a 550hp diesel weight with strut, shaft, prop, tranny. All relative. I wouldnt want one or two but i know some people that will. Whats Thiland putting out these days?
     
  4. brian eiland
    Joined: Jun 2002
    Posts: 4,962
    Likes: 184, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    7 Marine 557 Outboard

    If its a belt?, ...and I do suppose it is...my bet, it's a silent chain. It will be interesting to find out.

    But then the manner in which it is configured down lower indicates the power must go thru two more 90 degree turns??

    Eric Davis was asked how the engine’s power made the 90-degree change in direction to mate to a drive shaft, and he just shrugged and smiled. “I’ll have to explain that to you later,” he said. Apparently the Seven team is not ready to reveal all of its secrets.

    We do know that shifting is accomplished above the gearcase. The gearcase has a four-inch-diameter tube – a standard size – but has twin pinion gears to transfer power from the vertical drive shaft to the horizontal prop shaft, while keeping the size of the case small and hydrodynamic.
     
  5. BMcF
    Joined: Mar 2007
    Posts: 1,038
    Likes: 66, Points: 48, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

    Finally found the details for the belt-drive splitter box we built. To reiterate..the input (center) was driven at 5500 RPM and 450 HP by a modified big block Ford V-8.

    The box itself is all aluminum plate, both pinned and bolted at the edges.

    Both output shafts were connected to Berkeley 12JG jets (aft) and a hydraulic pump and cooling water pump (fwd). Engine and jet connecting shafts were all cardan type.
     

    Attached Files:

  6. anthony goodson
    Joined: Mar 2007
    Posts: 439
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    BMcF very simple and straightforward design just what I had expected to see. The fact that it runs jets ,gets over the reversing problem , and the need for thrust bearings .Thankyou for sharing that with us.
     
  7. fpjeepy05
    Joined: Jan 2010
    Posts: 248
    Likes: 14, Points: 18, Legacy Rep: 31
    Location: Hubert, NC

    fpjeepy05 Senior Member

    Beautiful. I like it. Jets do make it simpler. What kind of belt was it again? And how well did it hold up? How much was it used?

    Aside I found this [​IMG]
    Its a 35hp Mud Motor. That uses a Good Year timing belt. W-1120. PDF Replacement Guide

    Eagle Belts
    They use that belt to transmit up to 50 hp in there products, and from what I've read not too many problems. Linear extrapolation puts the Eagle PD Red at about 145hp. So it doesn't seem too difficult for up to that kind of power. Anything more would get more and more difficult.
     
    1 person likes this.
  8. BMcF
    Joined: Mar 2007
    Posts: 1,038
    Likes: 66, Points: 48, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

    We used Dayco (I think I earlier mispoke and said Gates..) RPP Synchro-Cog belts and pulleys. 85mm width, 14mm pitch.

    Even though we 'erred' on the power side of the design in favor of keeping box weight and size minimal, we never saw any sign of wear..no 'belt dust'...never had to adjust belt tension over the 400 or so hours that we operated the test craft (a 13.5m hydrofoil).

    A short duration..but with no indication of wear or problems, I would be quite confident to suggest that several thousand operating hours would be easily achieved...many more if it were not being operated at 5500 RPM all the time.:D
     
    1 person likes this.
  9. nordvindcrew
    Joined: Sep 2006
    Posts: 541
    Likes: 13, Points: 18, Legacy Rep: 231
    Location: Marshfield massachusetts usa

    nordvindcrew Senior Member

    alternate drive systems

    The late Rob White of Mississippi (?) built an atkin derived boat; the rescue minor. it used a friction drive and seemed to work well. perhaps hs son, who worked with him could help with details.
     
  10. BMcF
    Joined: Mar 2007
    Posts: 1,038
    Likes: 66, Points: 48, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

    Fun with belt drives.

    Here is another one we built..twin jets in a 55' LOA catamaran unmanned RC model (SES actually) hull with a single Honda 18HP V-twin for power.
     

    Attached Files:

    1 person likes this.
  11. brian eiland
    Joined: Jun 2002
    Posts: 4,962
    Likes: 184, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  12. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 110, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    How could you have a soft mount engine tensioning the belt?

    Most car and truck engines are fitted with a spring powered belt tensioner.

    Dozens to choose from at the parts counter OTS>
     
  13. brian eiland
    Joined: Jun 2002
    Posts: 4,962
    Likes: 184, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    That's a good question Fred. It does require some extra thought in design and installation.

    In the case that I brought up with this PYI unit I mentioned and photoed back HERE
    the drive unit itself is an individual unit that is subsequently joined to the soft mounted engine by some sort of drive shaft with CV type joints.

    Of course there were other units such as 'sail drives' that directly connected the engine to the drive train, and then soft mounted the whole unit into the hull with waterproof diaphrams.
     
  14. brian eiland
    Joined: Jun 2002
    Posts: 4,962
    Likes: 184, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    There was no development monies available.

    I had started out thinking Kevlar belts, but became convinced that the silent chain was a better idea. Here is a posting (2004) where I was going thru that transition:
    YachtForums.Com - View Single Post - New Drive System from Volvo Penta

    PYI had come out with a chain drive leg, but only marketed it for a few years. I'll see if I have a few other photos of it. I did collect a lot of info on these silent chains and identified a prime manufacturer I wished to work with on development of such an outdrive leg,...if some development monies should become available.

    One sample installation I saved on my older computer
    Paradise 60 :: Paradise Yachts

    One older spec sheet on the smaller sized unit:
     

    Attached Files:


  15. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 110, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    IF I were planning on a belt drive I would attempt to put 2 spring belt tensioners working paired so the engine would not be pulled to one side by the tension..
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.